National Instruments IMAQTM 用户手册

NI-IMAQ

The driver software for National Instruments IMAQ hardware.

nonlinear filter

Replaces each pixel value with a nonlinear function of its surrounding 
pixels.

nonlinear 
gradient filter

A highpass edge-extraction filter that favors vertical edges.

nonlinear Prewitt filter

A highpass, edge-extraction filter based on two-dimensional gradient 
information.

nonlinear Sobel filter

A highpass, edge-extraction filter based on two-dimensional gradient 
information. The filter has a smoothing effect that reduces noise 
enhancements caused by gradient operators.

Nth order filter

Filters an image using a nonlinear filter. This filter orders (or classifies) 
the pixel values surrounding the pixel being processed. The pixel being 
processed is set to the Nth pixel value, where N is the order of the filter.

number of planes 
(in an image)

The number of arrays of pixels that compose the image. A gray-level or 
pseudo-color image is composed of one plane, while an RGB image is 
composed of three planes (one for the red component, one for the blue, 
and one for the green).

OCR

Optical Character Recognition. The ability of a machine to read 
human-readable text.

OCV

Optical Character Verification. A machine vision application that inspects 
the quality of printed characters.

offset

The coordinate position in an image where you want to place the origin of 
another image. Setting an offset is useful when performing mask 
operations.

opening

An erosion followed by a dilation. An opening removes small objects and 
smooths boundaries of objects in the image.

operators

Allow masking, combination, and comparison of images. You can use 
arithmetic and logic operators in IMAQ Vision.